Humans have placed a thin layer of technology between themselves and nature: architecture, clothing, shared reserves. But we have never escaped the direct impact of the forces of nature. Extreme weather events have always been part of the reality of human life.

Likewise, attempts to actively influence the weather have been documented in many cultures: from Vedic rain-making rituals in ancient India, via the many wind myths of the ancient Greeks, through to modern examples from the German-speaking Alps that involve the ringing of church bells or firing cannons. Often, control over the weather was attributed to gods, witches or demons whose plans and powers were to be influenced by rituals as a way of protecting humans from the consequences of drought, storms or hail.

Later, people looked for physical causes of what they were observing. According to some anecdotes, for example, battles were often followed by rain. In 1891, with a keen interest in the truth about the weather, the US Department of Agriculture commissioned the solider and attorney Robert Saint George Dy’renforth to detonate large quantities of gunpowder, whose clouds of smoke had been credited with a rain-making effect. The experiment failed, earning its organiser the nickname “Dry-Henceforth”, as well as making people realise that the explanation probably lay in the human preference for making war in fair conditions. Good weather is followed by bad weather, eventually – an effect known in statistics as regression toward the mean.

The astonishing thing about the history of such attempts to shape the weather is their topicality, for in spite of their contested effectiveness, many techniques are very much in use. One example is “cloud seeding”, a technological heir to Dy’renforth’s experiments, developed in 1946 by a team led by Bernard Vonnegut (the brother of writer Kurt Vonnegut) at General Electric in Schenectady, New York, that involves injecting clouds with artificial condensation nuclei of silver iodide. This is done to increase the amount of precipitation in agricultural regions threatened by drought, like California’s Central Valley, or to defend against hail damage, as with the planes stationed at Stuttgart airport whose brief is to protect nearby vineyards from hailstorms, as well as the freshly manufactured cars waiting to be shipped out from the Mercedes-Benz factory. The benefit of such measures is not clear, but the threat posed by nature seems to justify their ongoing use. In the People’s Republic of China, attempts to actively shape the weather have taken on far greater proportions: during the Olympic Games of 2008, there were reports about a state “bureau of weather modification” that was tasked with using tens of thousands of artillery pieces and rockets loaded with silver iodide to keep rain away from Beijing. Another project presented in March 2018 aims to use cloud seeding to increase the annual rain volume on the Tibetan plateau by ten billion cubic metres, thus helping to secure the supply of fresh water to half of humanity – in anticipation of a future with rising temperatures.

But this future only opened up with the formal measurement and logging of weather that began in Germany, for example, at the Hohenpeißenberg Observatory in 1781. Thanks to the recording and statistical analysis of data, what used to be perceived individually was transformed into something systemic and local weather became part of the global climate, the two inseparably linked. In the second half of the twentieth century, computer simulation models showed conclusively that the use of fossil fuels influences the planet’s energy balance by making temperatures rise. Since becoming something produced by the climate, weather has also taken on a new significance. Whereas in the past, a drought impacted one region, perhaps a whole country, the factual increase in extreme weather events is now being viewed in connection with a change in climate that poses a potential threat to the survival of large parts of humanity.

In the course of this development, shaping the weather has given way to attempts to shape the climate as a means of securing human existence. First mentioned in 1965 in a scientific report to the then US president Lyndon B. Johnson, it has been the subject of heated debate since a 2006 article by the Dutch atmospheric chemist Paul J. Crutzen. The main approaches associated with such “climate engineering” are active carbon dioxide removal from the atmosphere (for example by large-scale reforestation), the controversial practice of iron-fertilising oceans to promote the growth of phytoplankton or the “scrubbing” of carbon dioxide from the atmosphere by artificial filters.

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Hagelkanone/hail canon, Kressbronn am Bodensee

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Hagelkanone/hail canon, 1973

Even more controversial than such “negative emission” approaches is the so-called solar radiation management that involves direct intervention in the global energy balance as a way of countering global warming. As early as 1974, the Russian climatologist Mikhail Budyko suggested releasing several hundred thousand tons of sulphates into the stratosphere that would act as artificial clouds, increasing the Earth’s albedo (its natural capacity for reflecting solar irradiation), “in order to maintain current climatic conditions” into the future. And indeed, many of the climate models underlying the politically threatened Paris Agreement (that aims to limit warming to two degrees Celsius compared with the pre-industrial age) already contain at least the use of negative emission technologies.

Opponents claim that even considering actively shaping the climate represents a “moral hazard” that distracts attention from reducing greenhouse gases. One dilemma is that solar radiation management technologies are comparatively trivial and inexpensive, with guaranteed effectiveness. This was proven not least by the “natural experiment” of the eruption of the Mount Pinatubo volcano on the Philippines in 1991 which led, via the same mechanism, to a globally measured fall in temperature of half a degree Celsius within a few months. The challenge here is more one of knowledge: predicting the exact impact of such an intervention and its consequences would call for climate simulations more detailed by several orders of magnitude than those available today. Climate engineering thus faces the opposite problem to that of weather modification: while the latter is applied on a large scale and no one knows if it has a statistically significant impact, the former is stuck in a crisis of imperfect knowledge and the resulting “precautionary principle”, which in this case means – doing nothing. Not least because the distinction between experimentation and global application is purely academic – one reason why applied fundamental research in climate engineering is met with resistance.

In the twenty-first century, however, similarities between shaping the weather and shaping the climate are likely to emerge, as destructive extreme weather attributable to human causes becomes more frequent and a critical mass of the world population may be faced with a “crisis” in the original sense of the word – a decision. Apart from the decision to make one’s lifestyle radically more climate-friendly (always the privilege of those who generate most of the greenhouse gases in the first place) this could also be a decision about measures with a short-term impact: the choice between an unintentionally altered world, resulting in the disaster area of centuries of overshooting the two degrees Celsius of Paris, or a world with the uncertainties of active climate management – something that, paradoxically, might preserve an environment with living conditions at least similar to those we are familiar with.

The prospect of a crisis raises more questions: If we knew with near certainty about the effects of a certain climate-shaping technology, would a majority be prepared to use it in order to at least partially halt the sixth mass extinction event in the planet’s history? Would we be prepared to leave the actual implementation of our wishes to an artificial intelligence if we knew that it alone was capable of providing the necessary brain power? In the Anthropocene, is it even possible for humankind to set itself apart from nature? What exact historical responsibility to whom (or what) results from the unequal world of humans? And what would be the political processes needed to make such a decision in an equitable way?

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National Oceanic and Atmospheric Administration (NOAA), orographic lift of moist air coming off ocean produces clouds along the Santa Lucia Mountains south of Monterey, California, Big Sur Coastline, photo: Robert Schwemmer

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National Oceanic and Atmospheric Administration (NOAA), Skies ablaze on the high plains, North Dakota, Steele, photo: Jeremy Bower

These are just a few of the issues that the United Nations, many national governments, research institutes and NGOs, as well as other stakeholders like reinsurance companies, must deal with. Regardless of what will, or will not happen in the context of man-made global climate change – it is already the largest design project in human history.